Polarizing plates have been used in various display devices such as liquid crystal display devices and organic light emitting diodes. Most polarizing plates currently used are used in a form of dyeing iodine and/or dichroic dye on a polyvinyl alcohol (hereinafter, PVA)-based film, crosslinking the iodine and/or dichroic dye using boric acid and the like, and orienting the result using a method of elongation to prepare a Polarizer, and laminating a protective film on one surface or both surfaces of the prepared Polarizer.
Meanwhile, recent display devices tend to be slimmer, and a thickness of a bezel unit, in which a screen is not displayed, and an edge thickness tend to be minimized in order to obtain a large screen. In addition, components such as a camera tend to be installed in a display device in order to exhibit various functions, and attempts to provide various colors in a product logo or an edge area have been tried considering design factors.
However, in an existing polarizing plate, the whole area of the polarizing plate is dyed with iodine and/or dichroic dye, therefore, the polarizing plate exhibits a dark black color, and as a result, various colors are difficult to be provided in an area that the polarizing plate is located, and particularly, when a polarizing plate is located on components such as a camera, the polarizing plate absorbs 50% or greater of the quantity of light causing a problem such as visibility decline in a camera lens.
In order to solve such a problem, a method of physically removing some areas of a polarizing plate through punching or cutting has been used. However, in this case, a problem of tearing a polarizing plate may occur during punching or cutting the polarizing plate, and such a problem becomes more serious with a recent trend of a polarizing plate becoming thinner. In addition, the punched or cut area needs to be sufficiently distant from an edge of the polarizing plate in order to punch or cut the polarizing plate without damage, however, this has a problem of not being suitable for a recent design trend of decreasing a bezel unit area.
The applicant of the present invention developed a technology of locally bleaching a polyvinyl alcohol-based polarizer using a strong basic solution in order to solve such a problem, and applied for a patent on the technology (Korean Patent Application No. 10-2014-0006269). However, in the patent technology, there has been a problem in that swelling occurs due to a strong basic solution during bleaching, and the bleached part is swollen compared to other parts, and as a result, wrinkles and deformation occur in a polarizer leading to an increase in haze, and the like.